1. Technical Field
The present invention relates to Fibre Channel adapters and, in particular, to adding a device to a Fibre Channel Arbitrated Loop. Still more particularly, the present invention provides a method, apparatus, and program for detecting a new device and reconfiguring a Fibre Channel loop.
2. Description of the Related Art
Fibre Channel is a high-speed transport technology used to build Storage Area Networks (SANs). Fibre Channel can be configured point-to-point, via a switched topology or in a Fibre Channel Arbitrated Loop (FCAL). An arbitrated loop can connect up to 127 nodes without using a switch. In a FCAL, all devices share the bandwidth, and only two devices can communicate with each other at the same time, with each node repeating data to its adjacent node. A Fibre Channel adapter with an arbitrated loop may have two or more connectors for connecting devices. A port bypass circuit may be used to configure the loop to include devices connected to these ports.
Adding a device to the loop may require manual configuration of the adapter software to include the device. The software running in the controller must then break the loop, reconfigure the port bypass circuit to add the corresponding connector to the loop, and check for loop integrity. If the software detects that the loop is open, then the port bypass must be reconfigured to bypass a connector. Auto detection algorithms may be added to the software to determine when a device is added. However, these algorithms add software overhead, which significantly impacts the performance of the controller.
Therefore, it would be advantageous to provide an improved mechanism for detecting new devices added a controller and reconfiguring the Fibre Channel Arbitrated Loop.